Blame view

net/llc/llc_sap.c 11.4 KB
1da177e4c   Linus Torvalds   Linux-2.6.12-rc2
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
  /*
   * llc_sap.c - driver routines for SAP component.
   *
   * Copyright (c) 1997 by Procom Technology, Inc.
   * 		 2001-2003 by Arnaldo Carvalho de Melo <acme@conectiva.com.br>
   *
   * This program can be redistributed or modified under the terms of the
   * GNU General Public License as published by the Free Software Foundation.
   * This program is distributed without any warranty or implied warranty
   * of merchantability or fitness for a particular purpose.
   *
   * See the GNU General Public License for more details.
   */
  
  #include <net/llc.h>
  #include <net/llc_if.h>
  #include <net/llc_conn.h>
  #include <net/llc_pdu.h>
  #include <net/llc_sap.h>
  #include <net/llc_s_ac.h>
  #include <net/llc_s_ev.h>
  #include <net/llc_s_st.h>
  #include <net/sock.h>
c752f0739   Arnaldo Carvalho de Melo   [TCP]: Move the t...
24
  #include <net/tcp_states.h>
1da177e4c   Linus Torvalds   Linux-2.6.12-rc2
25
  #include <linux/llc.h>
5a0e3ad6a   Tejun Heo   include cleanup: ...
26
  #include <linux/slab.h>
1da177e4c   Linus Torvalds   Linux-2.6.12-rc2
27

f83f1768f   Joonwoo Park   [LLC]: skb alloca...
28
29
30
31
32
33
  static int llc_mac_header_len(unsigned short devtype)
  {
  	switch (devtype) {
  	case ARPHRD_ETHER:
  	case ARPHRD_LOOPBACK:
  		return sizeof(struct ethhdr);
f0ecde146   David S. Miller   net: Fix FDDI and...
34
  #if defined(CONFIG_TR) || defined(CONFIG_TR_MODULE)
f83f1768f   Joonwoo Park   [LLC]: skb alloca...
35
36
37
38
39
40
  	case ARPHRD_IEEE802_TR:
  		return sizeof(struct trh_hdr);
  #endif
  	}
  	return 0;
  }
1da177e4c   Linus Torvalds   Linux-2.6.12-rc2
41
42
  /**
   *	llc_alloc_frame - allocates sk_buff for frame
1d67e6501   Arnaldo Carvalho de Melo   [LLC]: Make llc_f...
43
   *	@dev: network device this skb will be sent over
f83f1768f   Joonwoo Park   [LLC]: skb alloca...
44
45
   *	@type: pdu type to allocate
   *	@data_size: data size to allocate
1da177e4c   Linus Torvalds   Linux-2.6.12-rc2
46
47
48
49
   *
   *	Allocates an sk_buff for frame and initializes sk_buff fields.
   *	Returns allocated skb or %NULL when out of memory.
   */
f83f1768f   Joonwoo Park   [LLC]: skb alloca...
50
51
  struct sk_buff *llc_alloc_frame(struct sock *sk, struct net_device *dev,
  				u8 type, u32 data_size)
1da177e4c   Linus Torvalds   Linux-2.6.12-rc2
52
  {
f83f1768f   Joonwoo Park   [LLC]: skb alloca...
53
54
55
56
57
  	int hlen = type == LLC_PDU_TYPE_U ? 3 : 4;
  	struct sk_buff *skb;
  
  	hlen += llc_mac_header_len(dev->type);
  	skb = alloc_skb(hlen + data_size, GFP_ATOMIC);
1da177e4c   Linus Torvalds   Linux-2.6.12-rc2
58
59
  
  	if (skb) {
0a1b0ad9a   Arnaldo Carvalho de Melo   [LLC]: Use skb_re...
60
  		skb_reset_mac_header(skb);
f83f1768f   Joonwoo Park   [LLC]: skb alloca...
61
  		skb_reserve(skb, hlen);
c1d2bbe1c   Arnaldo Carvalho de Melo   [SK_BUFF]: Introd...
62
  		skb_reset_network_header(skb);
badff6d01   Arnaldo Carvalho de Melo   [SK_BUFF]: Introd...
63
  		skb_reset_transport_header(skb);
1da177e4c   Linus Torvalds   Linux-2.6.12-rc2
64
  		skb->protocol = htons(ETH_P_802_2);
1d67e6501   Arnaldo Carvalho de Melo   [LLC]: Make llc_f...
65
  		skb->dev      = dev;
d389424e0   Arnaldo Carvalho de Melo   [LLC]: Fix the ac...
66
67
  		if (sk != NULL)
  			skb_set_owner_w(skb, sk);
1da177e4c   Linus Torvalds   Linux-2.6.12-rc2
68
69
70
  	}
  	return skb;
  }
04e4223f4   Arnaldo Carvalho de Melo   [LLC]: Do better ...
71
  void llc_save_primitive(struct sock *sk, struct sk_buff* skb, u8 prim)
1da177e4c   Linus Torvalds   Linux-2.6.12-rc2
72
  {
8420e1b54   Arnaldo Carvalho de Melo   [LLC]: fix llc_ui...
73
  	struct sockaddr_llc *addr;
1da177e4c   Linus Torvalds   Linux-2.6.12-rc2
74
75
  
         /* save primitive for use by the user. */
8420e1b54   Arnaldo Carvalho de Melo   [LLC]: fix llc_ui...
76
  	addr		  = llc_ui_skb_cb(skb);
30a584d94   Stephen Hemminger   [LLX]: SOCK_DGRAM...
77
78
  
  	memset(addr, 0, sizeof(*addr));
04e4223f4   Arnaldo Carvalho de Melo   [LLC]: Do better ...
79
  	addr->sllc_family = sk->sk_family;
1da177e4c   Linus Torvalds   Linux-2.6.12-rc2
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
  	addr->sllc_arphrd = skb->dev->type;
  	addr->sllc_test   = prim == LLC_TEST_PRIM;
  	addr->sllc_xid    = prim == LLC_XID_PRIM;
  	addr->sllc_ua     = prim == LLC_DATAUNIT_PRIM;
  	llc_pdu_decode_sa(skb, addr->sllc_mac);
  	llc_pdu_decode_ssap(skb, &addr->sllc_sap);
  }
  
  /**
   *	llc_sap_rtn_pdu - Informs upper layer on rx of an UI, XID or TEST pdu.
   *	@sap: pointer to SAP
   *	@skb: received pdu
   */
  void llc_sap_rtn_pdu(struct llc_sap *sap, struct sk_buff *skb)
  {
  	struct llc_sap_state_ev *ev = llc_sap_ev(skb);
  	struct llc_pdu_un *pdu = llc_pdu_un_hdr(skb);
  
  	switch (LLC_U_PDU_RSP(pdu)) {
  	case LLC_1_PDU_CMD_TEST:
  		ev->prim = LLC_TEST_PRIM;	break;
  	case LLC_1_PDU_CMD_XID:
  		ev->prim = LLC_XID_PRIM;	break;
  	case LLC_1_PDU_CMD_UI:
  		ev->prim = LLC_DATAUNIT_PRIM;	break;
  	}
  	ev->ind_cfm_flag = LLC_IND;
  }
  
  /**
   *	llc_find_sap_trans - finds transition for event
   *	@sap: pointer to SAP
   *	@skb: happened event
   *
   *	This function finds transition that matches with happened event.
   *	Returns the pointer to found transition on success or %NULL for
   *	failure.
   */
  static struct llc_sap_state_trans *llc_find_sap_trans(struct llc_sap *sap,
  						      struct sk_buff* skb)
  {
  	int i = 0;
  	struct llc_sap_state_trans *rc = NULL;
  	struct llc_sap_state_trans **next_trans;
  	struct llc_sap_state *curr_state = &llc_sap_state_table[sap->state - 1];
  	/*
  	 * Search thru events for this state until list exhausted or until
  	 * its obvious the event is not valid for the current state
  	 */
  	for (next_trans = curr_state->transitions; next_trans[i]->ev; i++)
  		if (!next_trans[i]->ev(sap, skb)) {
  			rc = next_trans[i]; /* got event match; return it */
  			break;
  		}
  	return rc;
  }
  
  /**
   *	llc_exec_sap_trans_actions - execute actions related to event
   *	@sap: pointer to SAP
   *	@trans: pointer to transition that it's actions must be performed
   *	@skb: happened event.
   *
   *	This function executes actions that is related to happened event.
   *	Returns 0 for success and 1 for failure of at least one action.
   */
  static int llc_exec_sap_trans_actions(struct llc_sap *sap,
  				      struct llc_sap_state_trans *trans,
  				      struct sk_buff *skb)
  {
  	int rc = 0;
  	llc_sap_action_t *next_action = trans->ev_actions;
  
  	for (; next_action && *next_action; next_action++)
  		if ((*next_action)(sap, skb))
  			rc = 1;
  	return rc;
  }
  
  /**
   *	llc_sap_next_state - finds transition, execs actions & change SAP state
   *	@sap: pointer to SAP
   *	@skb: happened event
   *
   *	This function finds transition that matches with happened event, then
   *	executes related actions and finally changes state of SAP. It returns
   *	0 on success and 1 for failure.
   */
  static int llc_sap_next_state(struct llc_sap *sap, struct sk_buff *skb)
  {
  	int rc = 1;
  	struct llc_sap_state_trans *trans;
  
  	if (sap->state > LLC_NR_SAP_STATES)
  		goto out;
  	trans = llc_find_sap_trans(sap, skb);
  	if (!trans)
  		goto out;
  	/*
  	 * Got the state to which we next transition; perform the actions
  	 * associated with this transition before actually transitioning to the
  	 * next state
  	 */
  	rc = llc_exec_sap_trans_actions(sap, trans, skb);
  	if (rc)
  		goto out;
  	/*
  	 * Transition SAP to next state if all actions execute successfully
  	 */
  	sap->state = trans->next_state;
  out:
  	return rc;
  }
  
  /**
   *	llc_sap_state_process - sends event to SAP state machine
   *	@sap: sap to use
   *	@skb: pointer to occurred event
   *
   *	After executing actions of the event, upper layer will be indicated
   *	if needed(on receiving an UI frame). sk can be null for the
   *	datalink_proto case.
   */
  static void llc_sap_state_process(struct llc_sap *sap, struct sk_buff *skb)
  {
  	struct llc_sap_state_ev *ev = llc_sap_ev(skb);
  
  	/*
  	 * We have to hold the skb, because llc_sap_next_state
  	 * will kfree it in the sending path and we need to
  	 * look at the skb->cb, where we encode llc_sap_state_ev.
  	 */
  	skb_get(skb);
  	ev->ind_cfm_flag = 0;
  	llc_sap_next_state(sap, skb);
  	if (ev->ind_cfm_flag == LLC_IND) {
  		if (skb->sk->sk_state == TCP_LISTEN)
  			kfree_skb(skb);
  		else {
04e4223f4   Arnaldo Carvalho de Melo   [LLC]: Do better ...
219
  			llc_save_primitive(skb->sk, skb, ev->prim);
1da177e4c   Linus Torvalds   Linux-2.6.12-rc2
220
221
222
223
224
  
  			/* queue skb to the user. */
  			if (sock_queue_rcv_skb(skb->sk, skb))
  				kfree_skb(skb);
  		}
d57b1869b   YOSHIFUJI Hideaki   [NET] LLC: Fix wh...
225
  	}
1da177e4c   Linus Torvalds   Linux-2.6.12-rc2
226
227
228
229
230
231
232
233
234
235
236
237
238
  	kfree_skb(skb);
  }
  
  /**
   *	llc_build_and_send_test_pkt - TEST interface for upper layers.
   *	@sap: sap to use
   *	@skb: packet to send
   *	@dmac: destination mac address
   *	@dsap: destination sap
   *
   *	This function is called when upper layer wants to send a TEST pdu.
   *	Returns 0 for success, 1 otherwise.
   */
d57b1869b   YOSHIFUJI Hideaki   [NET] LLC: Fix wh...
239
  void llc_build_and_send_test_pkt(struct llc_sap *sap,
1da177e4c   Linus Torvalds   Linux-2.6.12-rc2
240
241
242
243
244
245
246
247
  				 struct sk_buff *skb, u8 *dmac, u8 dsap)
  {
  	struct llc_sap_state_ev *ev = llc_sap_ev(skb);
  
  	ev->saddr.lsap = sap->laddr.lsap;
  	ev->daddr.lsap = dsap;
  	memcpy(ev->saddr.mac, skb->dev->dev_addr, IFHWADDRLEN);
  	memcpy(ev->daddr.mac, dmac, IFHWADDRLEN);
d57b1869b   YOSHIFUJI Hideaki   [NET] LLC: Fix wh...
248

1da177e4c   Linus Torvalds   Linux-2.6.12-rc2
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
  	ev->type      = LLC_SAP_EV_TYPE_PRIM;
  	ev->prim      = LLC_TEST_PRIM;
  	ev->prim_type = LLC_PRIM_TYPE_REQ;
  	llc_sap_state_process(sap, skb);
  }
  
  /**
   *	llc_build_and_send_xid_pkt - XID interface for upper layers
   *	@sap: sap to use
   *	@skb: packet to send
   *	@dmac: destination mac address
   *	@dsap: destination sap
   *
   *	This function is called when upper layer wants to send a XID pdu.
   *	Returns 0 for success, 1 otherwise.
   */
  void llc_build_and_send_xid_pkt(struct llc_sap *sap, struct sk_buff *skb,
  				u8 *dmac, u8 dsap)
  {
  	struct llc_sap_state_ev *ev = llc_sap_ev(skb);
  
  	ev->saddr.lsap = sap->laddr.lsap;
  	ev->daddr.lsap = dsap;
  	memcpy(ev->saddr.mac, skb->dev->dev_addr, IFHWADDRLEN);
  	memcpy(ev->daddr.mac, dmac, IFHWADDRLEN);
  
  	ev->type      = LLC_SAP_EV_TYPE_PRIM;
  	ev->prim      = LLC_XID_PRIM;
  	ev->prim_type = LLC_PRIM_TYPE_REQ;
  	llc_sap_state_process(sap, skb);
  }
  
  /**
   *	llc_sap_rcv - sends received pdus to the sap state machine
   *	@sap: current sap component structure.
   *	@skb: received frame.
   *
   *	Sends received pdus to the sap state machine.
   */
3446b9d57   Arnaldo Carvalho de Melo   llc: Fix double a...
288
289
  static void llc_sap_rcv(struct llc_sap *sap, struct sk_buff *skb,
  			struct sock *sk)
1da177e4c   Linus Torvalds   Linux-2.6.12-rc2
290
291
292
293
294
  {
  	struct llc_sap_state_ev *ev = llc_sap_ev(skb);
  
  	ev->type   = LLC_SAP_EV_TYPE_PDU;
  	ev->reason = 0;
3446b9d57   Arnaldo Carvalho de Melo   llc: Fix double a...
295
  	skb->sk = sk;
1da177e4c   Linus Torvalds   Linux-2.6.12-rc2
296
297
  	llc_sap_state_process(sap, skb);
  }
b76f5a842   Octavian Purdila   llc: convert the ...
298
299
300
301
302
303
304
305
306
307
  static inline bool llc_dgram_match(const struct llc_sap *sap,
  				   const struct llc_addr *laddr,
  				   const struct sock *sk)
  {
       struct llc_sock *llc = llc_sk(sk);
  
       return sk->sk_type == SOCK_DGRAM &&
  	  llc->laddr.lsap == laddr->lsap &&
  	  llc_mac_match(llc->laddr.mac, laddr->mac);
  }
1da177e4c   Linus Torvalds   Linux-2.6.12-rc2
308
309
310
311
312
313
314
315
316
  /**
   *	llc_lookup_dgram - Finds dgram socket for the local sap/mac
   *	@sap: SAP
   *	@laddr: address of local LLC (MAC + SAP)
   *
   *	Search socket list of the SAP and finds connection using the local
   *	mac, and local sap. Returns pointer for socket found, %NULL otherwise.
   */
  static struct sock *llc_lookup_dgram(struct llc_sap *sap,
bc0e64679   Stephen Hemminger   [LLC]: add multic...
317
  				     const struct llc_addr *laddr)
1da177e4c   Linus Torvalds   Linux-2.6.12-rc2
318
319
  {
  	struct sock *rc;
b76f5a842   Octavian Purdila   llc: convert the ...
320
  	struct hlist_nulls_node *node;
52d58aef5   Octavian Purdila   llc: replace the ...
321
322
  	int slot = llc_sk_laddr_hashfn(sap, laddr);
  	struct hlist_nulls_head *laddr_hb = &sap->sk_laddr_hash[slot];
b76f5a842   Octavian Purdila   llc: convert the ...
323
324
325
  
  	rcu_read_lock_bh();
  again:
52d58aef5   Octavian Purdila   llc: replace the ...
326
  	sk_nulls_for_each_rcu(rc, node, laddr_hb) {
b76f5a842   Octavian Purdila   llc: convert the ...
327
328
329
330
331
332
333
334
335
  		if (llc_dgram_match(sap, laddr, rc)) {
  			/* Extra checks required by SLAB_DESTROY_BY_RCU */
  			if (unlikely(!atomic_inc_not_zero(&rc->sk_refcnt)))
  				goto again;
  			if (unlikely(llc_sk(rc)->sap != sap ||
  				     !llc_dgram_match(sap, laddr, rc))) {
  				sock_put(rc);
  				continue;
  			}
1da177e4c   Linus Torvalds   Linux-2.6.12-rc2
336
337
338
339
  			goto found;
  		}
  	}
  	rc = NULL;
52d58aef5   Octavian Purdila   llc: replace the ...
340
341
342
343
344
345
346
  	/*
  	 * if the nulls value we got at the end of this lookup is
  	 * not the expected one, we must restart lookup.
  	 * We probably met an item that was moved to another chain.
  	 */
  	if (unlikely(get_nulls_value(node) != slot))
  		goto again;
1da177e4c   Linus Torvalds   Linux-2.6.12-rc2
347
  found:
b76f5a842   Octavian Purdila   llc: convert the ...
348
  	rcu_read_unlock_bh();
1da177e4c   Linus Torvalds   Linux-2.6.12-rc2
349
350
  	return rc;
  }
b76f5a842   Octavian Purdila   llc: convert the ...
351
352
353
354
355
356
357
358
359
360
361
  static inline bool llc_mcast_match(const struct llc_sap *sap,
  				   const struct llc_addr *laddr,
  				   const struct sk_buff *skb,
  				   const struct sock *sk)
  {
       struct llc_sock *llc = llc_sk(sk);
  
       return sk->sk_type == SOCK_DGRAM &&
  	  llc->laddr.lsap == laddr->lsap &&
  	  llc->dev == skb->dev;
  }
0f7b67dd9   Octavian Purdila   llc: optimize mul...
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
  static void llc_do_mcast(struct llc_sap *sap, struct sk_buff *skb,
  			 struct sock **stack, int count)
  {
  	struct sk_buff *skb1;
  	int i;
  
  	for (i = 0; i < count; i++) {
  		skb1 = skb_clone(skb, GFP_ATOMIC);
  		if (!skb1) {
  			sock_put(stack[i]);
  			continue;
  		}
  
  		llc_sap_rcv(sap, skb1, stack[i]);
  		sock_put(stack[i]);
  	}
  }
bc0e64679   Stephen Hemminger   [LLC]: add multic...
379
380
381
382
383
384
385
386
387
388
389
390
  /**
   * 	llc_sap_mcast - Deliver multicast PDU's to all matching datagram sockets.
   *	@sap: SAP
   *	@laddr: address of local LLC (MAC + SAP)
   *
   *	Search socket list of the SAP and finds connections with same sap.
   *	Deliver clone to each.
   */
  static void llc_sap_mcast(struct llc_sap *sap,
  			  const struct llc_addr *laddr,
  			  struct sk_buff *skb)
  {
0f7b67dd9   Octavian Purdila   llc: optimize mul...
391
392
  	int i = 0, count = 256 / sizeof(struct sock *);
  	struct sock *sk, *stack[count];
6d2e3ea28   Octavian Purdila   llc: use a device...
393
394
395
  	struct hlist_node *node;
  	struct llc_sock *llc;
  	struct hlist_head *dev_hb = llc_sk_dev_hash(sap, skb->dev->ifindex);
bc0e64679   Stephen Hemminger   [LLC]: add multic...
396

b76f5a842   Octavian Purdila   llc: convert the ...
397
  	spin_lock_bh(&sap->sk_lock);
6d2e3ea28   Octavian Purdila   llc: use a device...
398
399
400
  	hlist_for_each_entry(llc, node, dev_hb, dev_hash_node) {
  
  		sk = &llc->sk;
bc0e64679   Stephen Hemminger   [LLC]: add multic...
401

b76f5a842   Octavian Purdila   llc: convert the ...
402
  		if (!llc_mcast_match(sap, laddr, skb, sk))
7ee66fcb9   Stephen Hemminger   [LLC]: multicast ...
403
  			continue;
bc0e64679   Stephen Hemminger   [LLC]: add multic...
404
  		sock_hold(sk);
0f7b67dd9   Octavian Purdila   llc: optimize mul...
405
406
407
408
409
410
  		if (i < count)
  			stack[i++] = sk;
  		else {
  			llc_do_mcast(sap, skb, stack, i);
  			i = 0;
  		}
bc0e64679   Stephen Hemminger   [LLC]: add multic...
411
  	}
b76f5a842   Octavian Purdila   llc: convert the ...
412
  	spin_unlock_bh(&sap->sk_lock);
0f7b67dd9   Octavian Purdila   llc: optimize mul...
413
414
  
  	llc_do_mcast(sap, skb, stack, i);
bc0e64679   Stephen Hemminger   [LLC]: add multic...
415
  }
1da177e4c   Linus Torvalds   Linux-2.6.12-rc2
416
417
418
  void llc_sap_handler(struct llc_sap *sap, struct sk_buff *skb)
  {
  	struct llc_addr laddr;
1da177e4c   Linus Torvalds   Linux-2.6.12-rc2
419
420
421
  
  	llc_pdu_decode_da(skb, laddr.mac);
  	llc_pdu_decode_dsap(skb, &laddr.lsap);
bc0e64679   Stephen Hemminger   [LLC]: add multic...
422
423
  	if (llc_mac_multicast(laddr.mac)) {
  		llc_sap_mcast(sap, &laddr, skb);
1da177e4c   Linus Torvalds   Linux-2.6.12-rc2
424
  		kfree_skb(skb);
bc0e64679   Stephen Hemminger   [LLC]: add multic...
425
426
427
  	} else {
  		struct sock *sk = llc_lookup_dgram(sap, &laddr);
  		if (sk) {
3446b9d57   Arnaldo Carvalho de Melo   llc: Fix double a...
428
  			llc_sap_rcv(sap, skb, sk);
bc0e64679   Stephen Hemminger   [LLC]: add multic...
429
430
431
432
  			sock_put(sk);
  		} else
  			kfree_skb(skb);
  	}
1da177e4c   Linus Torvalds   Linux-2.6.12-rc2
433
  }